Buggy code:
public boolean visit ( ArrayTypeReference arrayTypeReference , ClassScope scope ) { } public boolean visit ( AssertStatement assertStatement , BlockScope scope ) { } public boolean visit ( Assignment assignment , BlockScope scope ) { } public boolean visit ( BinaryExpression binaryExpression , BlockScope scope ) { } public boolean visit ( Block block , BlockScope scope ) { } public boolean visit ( BreakStatement breakStatement , BlockScope scope ) { } public boolean visit ( CaseStatement caseStatement , BlockScope scope ) { } public boolean visit ( CastExpression castExpression , BlockScope scope ) { } public boolean visit ( CharLiteral charLiteral , BlockScope scope ) { } public boolean visit ( ClassLiteralAccess classLiteral , BlockScope scope ) { } public boolean visit ( Clinit clinit , ClassScope scope ) { } public boolean visit ( CompilationUnitDeclaration compilationUnitDeclaration , CompilationUnitScope scope ) { } public boolean visit ( CompoundAssignment compoundAssignment , BlockScope scope ) { } public boolean visit ( ConditionalExpression conditionalExpression , BlockScope scope ) { } public boolean visit ( ConstructorDeclaration constructorDeclaration , ClassScope scope ) { } public boolean visit ( ContinueStatement continueStatement , BlockScope scope ) { } public boolean visit ( DoStatement doStatement , BlockScope scope ) { } public boolean visit ( DoubleLiteral doubleLiteral , BlockScope scope ) { } public boolean visit ( EmptyStatement statement , BlockScope scope ) { } public boolean visit ( EqualExpression equalExpression , BlockScope scope ) { } public boolean visit ( ExplicitConstructorCall explicitConstructor , BlockScope scope ) { } public boolean visit ( FalseLiteral falseLiteral , BlockScope scope ) { } public boolean visit ( FieldReference fieldReference , BlockScope scope ) { } public boolean visit ( FloatLiteral floatLiteral , BlockScope scope ) { } public boolean visit ( ForStatement forStatement , BlockScope scope ) { } public boolean visit ( IfStatement ifStatement , BlockScope scope ) { } public boolean visit ( ImportReference importRef , CompilationUnitScope scope ) { } public boolean visit ( Initializer initializer , MethodScope scope ) { } public boolean visit ( InstanceOfExpression instanceOfExpression , BlockScope scope ) { } public boolean visit ( IntLiteral intLiteral , BlockScope scope ) { } public boolean visit ( LabeledStatement labeledStatement , BlockScope scope ) { } public boolean visit ( LocalDeclaration localDeclaration , BlockScope scope ) { } public boolean visit ( LocalTypeDeclaration localTypeDeclaration , BlockScope scope ) { } public boolean visit ( LongLiteral longLiteral , BlockScope scope ) { } public boolean visit ( MemberTypeDeclaration memberTypeDeclaration , ClassScope scope ) { } public boolean visit ( MessageSend messageSend , BlockScope scope ) { } public boolean visit ( MethodDeclaration methodDeclaration , ClassScope scope ) { } public boolean visit ( NullLiteral nullLiteral , BlockScope scope ) { } public boolean visit ( OR_OR_Expression or_or_Expression , BlockScope scope ) { } public boolean visit ( PostfixExpression postfixExpression , BlockScope scope ) { } public boolean visit ( PrefixExpression prefixExpression , BlockScope scope ) { } public boolean visit ( QualifiedAllocationExpression qualifiedAllocationExpression , BlockScope scope ) { } public boolean visit ( QualifiedNameReference qualifiedNameReference , BlockScope scope ) { } public boolean visit ( QualifiedSuperReference qualifiedSuperReference , BlockScope scope ) { } public boolean visit ( QualifiedThisReference qualifiedThisReference , BlockScope scope ) { } public boolean visit ( QualifiedTypeReference qualifiedTypeReference , BlockScope scope ) { } public boolean visit ( QualifiedTypeReference qualifiedTypeReference , ClassScope scope ) { } public boolean visit ( ReturnStatement returnStatement , BlockScope scope ) { } public boolean visit ( SingleNameReference singleNameReference , BlockScope scope ) { } public boolean visit ( SingleTypeReference singleTypeReference , BlockScope scope ) { } public boolean visit ( SingleTypeReference singleTypeReference , ClassScope scope ) { } public boolean visit ( StringLiteral stringLiteral , BlockScope scope ) { } public boolean visit ( SuperReference superReference , BlockScope scope ) { } public boolean visit ( SwitchStatement switchStatement , BlockScope scope ) { this . scribe . printNextToken ( TerminalTokens . TokenNameswitch ) ; this . scribe . printNextToken ( TerminalTokens . TokenNameLPAREN , this . preferences . insert_space_before_switch_condition ) ; if ( this . preferences . insert_space_in_switch_condition ) { this . scribe . space ( ) ; } <START_BUG> switchStatement . testExpression . traverse ( this , scope ) ; <END_BUG> this . scribe . printNextToken ( TerminalTokens . TokenNameRPAREN , this . preferences . insert_space_in_switch_condition ) ; String switch_brace = this . preferences . switch_brace_position ; formatOpeningBrace ( switch_brace , this . preferences . insert_space_before_switch_open_brace ) ; this . scribe . printNewLine ( ) ; if ( preferences . indent_switchstatements_compare_to_switch ) { this . scribe . indent ( ) ; } final Statement [ ] statements = switchStatement . statements ; boolean wasACase = false ; boolean wasAStatement = false ; if ( statements != null ) { int statementsLength = statements . length ; for ( int i = 0 ; i < statementsLength ; i ++ ) { final Statement statement = statements [ i ] ; if ( statement instanceof CaseStatement ) { if ( ( wasACase && ( this . preferences . indent_switchstatements_compare_to_cases ) ) || ( wasAStatement && ( this . preferences . indent_switchstatements_compare_to_cases ) ) ) { this . scribe . unIndent ( ) ; } statement . traverse ( this , scope ) ; wasACase = true ; wasAStatement = false ; if ( this . preferences . indent_switchstatements_compare_to_cases ) { this . scribe . indent ( ) ; } } else if ( statement instanceof BreakStatement ) { if ( this . preferences . indent_breaks_compare_to_cases ) { if ( wasAStatement && ( ! ( this . preferences . indent_switchstatements_compare_to_cases ) ) ) { this . scribe . indent ( ) ; } } else { if ( wasAStatement ) { if ( this . preferences . indent_switchstatements_compare_to_cases ) { this . scribe . unIndent ( ) ; } } if ( wasACase && ( this . preferences . indent_switchstatements_compare_to_cases ) ) { this . scribe . unIndent ( ) ; }

Fix:
switchStatement . expression . traverse ( this , scope ) ;